"Although we suspected that strenuous police duties could trigger sudden cardiac deaths in vulnerable officers, we were struck by the magnitudes of the risks and their consistency across different statistical models," says senior author Dr. Stefanos Kales.

Serving as a police officer was judged to be the ninth most stressful job in America this year, according to job search website CareerCast. In 2011-2012, the fatality rate among patrol officers was 3-5 times the national average for private sector employees, at 15-16 people per 100,000 full-time wor...